The present invention relates generally to fluid flow control valves for automatically shutting off the flow of fluids in response to one or more sensed conditions necessitating such shutoff and, more particularly, to two-way two-position fluid flow control valves that are latchable at their opened position with only residual magnetism.
Known automatic fluid shutoff valves include those disclosed in U.S. Pat. No. 4,501,290 issued to Sturman et al. on Feb. 26, 1985. In FIGS. 2-3 of Sturman et al., a pressure regulating electrically operable shutoff valve is shown having a permanent magnet 84 that is used to latch a third magnetic member 98 with a magnetic member 82. One disadvantage of using permanent magnets to help create a magnetic circuit is their inherent brittleness and consequent susceptibility to breaking if accidentally dropped during assembly or disassembly. Another disadvantage of permanent magnets is their tendency to constantly attract and collect magnetically attractive debris between the moving and stationary parts of the magnetic circuit. Such debris may, for example, be introduced during the assembly process. Such debris can prevent the moving and opposing stationary parts of the magnetic circuit from achieving substantially zero air gap therebetween and therefore prevent desired latching.
In FIGS. 1-2 of U.S. Pat. No. 6,481,689 B2 issued to Grill on Nov. 19, 2002, there is shown a two-way two-position fluid control valve having a solenoid 48. When the solenoid 48 is electrically actuated, an armature 58 is pulled into contact with a core 56 while a transfer tube 42, and a valve 26 coupled to the transfer tube 42, move from a first (closed) position shown in FIG. 1 to a second (opened) position shown in FIG. 2. While the fluid control valve of Grill is suitable for many applications, the solenoid 48 disclosed therein for both i) electromagnetically pulling the armature 58 (and valve 26) from its closed position to its opened position and ii) holding the armature 48 (and valve 26) in its opened position may be unsuitable for other applications. For example, it may be too expensive and/or too power consuming for certain automatic fluid shutoff applications, such as those found in various places of the common household.
It is therefore desirable to provide an automatic fluid shutoff valve that features simplicity of design and operation, energy efficiency, reliability, and relatively low manufacturing cost.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention, there is disclosed a 2-way 2-position fluid control valve assembly operable to selectively open and block fluid flow therethrough. The fluid control valve assembly includes a valve and an electromagnetic actuator having a movable armature portion and a stationary stator portion. The valve is biased to its closed position whereat the armature portion is spaced away from the stator portion. The armature portion is manually movable to contact the stator portion while opening the valve. The armature portion and stator portion are latachable together, with only residual magnetism, only when there is zero air gap or substantially zero air gap between the armature portion and the stator portion. When latched, the armature portion and the stator portion remain in their latched state with the valve maintained at its opened position until the armature portion and the stator portion are delatched by canceling at least enough of the residual magnetism so that the biased valve closes while the armature portion moves away from the stator portion.
In another aspect of the present invention, there is disclosed a method of operating a 2-way 2-position fluid control valve assembly including a valve and an electromagnetic actuator having an armature portion and a stator portion. The method comprises the steps of biasing the valve to its closed position whereat the armature portion is spaced away from the stator portion, opening the valve by manually moving the armature portion into zero air gap or substantially zero air gap with the stator portion, maintaining the valve at its opened position by latching the armature portion and the stator portion together with only residual magnetism, and closing the valve by canceling at least enough of the residual magnetism between the armature portion and the stator portion to allow the biased valve to move to its closed position.
The subject invention advantageously provides a two-way two-position fluid control valve assembly for automatically shutting off fluid flow in various household and commercial applications. The control valve assembly advantageously features simplicity of design and operation, energy efficiency, reliability, and relatively low cost to manufacture.